JP6291165B2 - Manufacturing method of connecting body and connecting method of electronic component - Google Patents

Description

  The present invention relates to a method for manufacturing a connection body in which electronic components and the like are connected using a photocurable adhesive, and a connection method for connecting electronic components and the like using a photocurable adhesive.

  Conventionally, a liquid crystal display device has been widely used as various display means such as a television, a PC monitor, a mobile phone, a portable game machine, a tablet PC, or an in-vehicle monitor. In recent years, in such liquid crystal display devices, so-called COG (chip on glass) in which a liquid crystal driving IC is directly mounted on a substrate of a liquid crystal display panel, or a liquid crystal driving circuit, from the viewpoint of fine pitch, light weight and thinning A so-called FOG (film on glass) that directly mounts the flexible substrate on which the substrate is formed on the substrate of the liquid crystal display panel is employed.

  For example, as shown in FIG. 8, a liquid crystal display device 100 employing a COG mounting system has a liquid crystal display panel 104 that performs a main function for liquid crystal display. The liquid crystal display panel 104 includes a glass substrate or the like. And two transparent substrates 102 and 103 facing each other. In the liquid crystal display panel 104, the transparent substrates 102 and 103 are bonded to each other by a frame-shaped seal 105, and the liquid crystal 106 is sealed in a space surrounded by the transparent substrates 102 and 103 and the seal 105. A panel display unit 107 is provided.

  The transparent substrates 102 and 103 have a pair of striped transparent electrodes 108 and 109 made of ITO (indium tin oxide) or the like on both inner surfaces facing each other so as to intersect each other. In the transparent substrates 102 and 103, a pixel as a minimum unit for liquid crystal display is configured by the intersection of the transparent electrodes 108 and 109.

  Of the two transparent substrates 102 and 103, one transparent substrate 103 is formed to have a larger planar dimension than the other transparent substrate 102, and the transparent electrode 109 is formed on the edge 103a of the transparent substrate 103 formed to be large. Terminal portion 109a is formed. In addition, alignment films 111 and 112 subjected to a predetermined rubbing process are formed on both transparent electrodes 108 and 109, and the initial alignment of liquid crystal molecules is regulated by the alignment films 111 and 112. Further, a pair of polarizing plates 118 and 119 are disposed outside the transparent electrodes 108 and 109, and the vibration direction of transmitted light from the light source 120 such as a backlight is regulated by the polarizing plates 118 and 119. Is done.

  On the terminal portion 109a, a liquid crystal driving IC 115 is thermocompression bonded via an anisotropic conductive film 114. The anisotropic conductive film 114 is a film formed by mixing conductive particles in a thermosetting binder resin, and heat conduction is performed between the two conductors so that the electrical conduction between the conductors is achieved by the conductive particles. And the mechanical connection between the conductors is maintained by the binder resin. The liquid crystal driving IC 115 can perform predetermined liquid crystal display by selectively applying a liquid crystal driving voltage to the pixels to partially change the alignment of the liquid crystal. Note that as the adhesive constituting the anisotropic conductive film 114, the most reliable thermosetting adhesive is usually used.

  When the liquid crystal driving IC 115 is connected to the terminal portion 109a through such an anisotropic conductive film 114, first, the anisotropic conductive film 114 is attached to the terminal portion 109a of the transparent electrode 109 by a temporary crimping means (not shown). Temporarily crimp. Subsequently, after the liquid crystal driving IC 115 is mounted on the anisotropic conductive film 114, the liquid crystal driving IC 115 is connected to the terminal together with the anisotropic conductive film 114 by thermocompression bonding means 121 such as a thermocompression bonding head as shown in FIG. The thermocompression bonding means 121 is caused to generate heat while being pressed toward the portion 109a. Due to the heat generated by the thermocompression bonding means 121, the anisotropic conductive film 114 undergoes a thermosetting reaction, whereby the liquid crystal driving IC 115 is bonded onto the terminal portion 109a via the anisotropic conductive film 114.

  However, in such a connection method using an anisotropic conductive film, the heat pressing temperature is high, and the thermal shock to the electronic components such as the liquid crystal driving IC 115 and the transparent substrate 103 is increased.

  Therefore, a connection method using an ultraviolet curable adhesive instead of the anisotropic conductive film 114 using such a thermosetting adhesive has been proposed. In the connection method using the ultraviolet curable adhesive, the adhesive softens and flows due to heat, and the temperature is high enough to sandwich the conductive particles between the terminal portion 109a of the transparent electrode 109 and the electrode of the liquid crystal driving IC 115. Stop heating and cure the adhesive by UV irradiation.

  However, even in such a connection method using an ultraviolet curable adhesive, the adhesive shrinks as it is cured by ultraviolet irradiation. Therefore, due to the shrinkage, the IC connection portion of the transparent substrate 103 that sandwiches the liquid crystal 106 is warped, so that the surface uniformity of the gap between the transparent substrates 102 and 103 in the panel display portion 107 is lost. The orientation of the liquid crystal is disturbed, and there is a risk of causing problems such as display unevenness. Further, there is a risk of causing a connection failure of the liquid crystal driving IC 115 due to the warp generated in the IC connection portion of the transparent substrate 103.

WO00 / 46315 publication

  Therefore, the present invention solves the above-described problems, and by using an ultraviolet curable adhesive, the electronic component is connected at a low temperature, and distortion caused by curing shrinkage of the adhesive is suppressed. It is an object of the present invention to provide a method for manufacturing a connection body that improves poor connection and a method for connecting an electronic component.

In order to solve the above-described problems, a method for manufacturing a connection body in which an electronic component is connected on a substrate according to the present invention includes a step of arranging the electronic component on the substrate via a photo-curing adhesive. And a step of irradiating the adhesive with light to cure. An area where the substrate and the electronic component are connected is divided into a plurality of connection areas. For each connection area, an irradiation section that irradiates the light corresponding to the connection area is equal to an adjacent irradiation section. The partial irradiation ranges overlap, and the light irradiation intensity is changed and cured.

According to the present invention, an electronic component connecting method for connecting an electronic component on a substrate includes a step of placing the electronic component on the substrate via a photo-curing adhesive, and irradiating the adhesive with light. And curing. An area where the substrate and the electronic component are connected is divided into a plurality of connection areas. For each connection area, an irradiation section that irradiates the light corresponding to the connection area is equal to an adjacent irradiation section. The electronic components are connected on the substrate , where the partial irradiation ranges overlap and are cured by changing the light irradiation intensity.

  According to the present invention, by changing the irradiation intensity, the timing of curing can be made different for each connection region, and the connection between the electronic component and the substrate can be achieved while sequentially absorbing the distortion caused by the curing shrinkage in each connection region. .

It is sectional drawing which shows the mounting process to which this invention was applied. It is sectional drawing which shows an anisotropic conductive film. It is a perspective view which shows the connection area | region formed by connecting an electronic component and a glass substrate. It is a top view which shows the ultraviolet irradiation intensity | strength of the 1st-5th connection area | region. It is a figure for demonstrating the measuring method of the curvature of the glass substrate which concerns on an Example and a comparative example. It is a figure for demonstrating the measuring method of the conduction resistance which concerns on an Example and a comparative example. It is a figure which shows the relationship between the ultraviolet irradiation time of each ultraviolet irradiation intensity | strength, and the reaction rate. It is sectional drawing which shows the conventional liquid crystal display panel. It is sectional drawing which shows the COG mounting process of the conventional liquid crystal display panel.

  Hereinafter, a manufacturing method and a connecting method of a connection body to which the present invention is applied will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. Further, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Specific dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  In the following, a case where an electronic component is connected to a substrate as an object to be connected and an object to be connected will be described as an example. However, the present technology can be applied to other than the connection between the substrate and the electronic component. For example, so-called COG (chip on glass) mounting is performed in which an IC chip for driving a liquid crystal is mounted on a glass substrate of a liquid crystal display panel. As shown in FIG. 1, the liquid crystal display panel 10 includes two transparent substrates 11 and 12 made of a glass substrate and the like, and the transparent substrates 11 and 12 are bonded to each other by a frame-shaped seal 13. . In the liquid crystal display panel 10, the liquid crystal 14 is sealed in a space surrounded by the transparent substrates 11 and 12 to form a panel display unit 15.

  The transparent substrates 11 and 12 have a pair of striped transparent electrodes 16 and 17 made of ITO (indium tin oxide) or the like on both inner surfaces facing each other so as to intersect each other. The transparent electrodes 16 and 17 constitute a pixel as a minimum unit for liquid crystal display by the intersection of the transparent electrodes 16 and 17.

  Of the transparent substrates 11 and 12, one transparent substrate 12 is formed to have a larger planar dimension than the other transparent substrate 11, and a liquid crystal driving edge is formed on the edge 12a of the formed transparent substrate 12. A COG mounting unit 20 on which an electronic component 18 such as an IC is mounted is provided, and an FOG mounting unit 22 on which a flexible substrate 21 on which a liquid crystal driving circuit is formed is mounted near the outside of the COG mounting unit 20. ing.

  Note that the liquid crystal driving IC and the liquid crystal driving circuit perform predetermined liquid crystal display by partially changing the alignment of the liquid crystal by selectively applying a liquid crystal driving voltage to the pixels.

  In each of the mounting portions 20 and 22, a terminal portion 17a of the transparent electrode 17 is formed. On the terminal portion 17a, an electronic component 18 such as a liquid crystal driving IC and a flexible substrate 21 are connected using the anisotropic conductive film 1 as a conductive adhesive. The anisotropic conductive film 1 contains the conductive particles 4, and conducts the electrode of the electronic component 18 or the flexible substrate 21 and the terminal portion 17 a of the transparent electrode 17 formed on the edge portion 12 a of the transparent substrate 12. Electrical connection is made through the conductive particles 4. The anisotropic conductive film 1 is an ultraviolet curable adhesive and is fluidized by being thermocompression-bonded by a heating and pressing head 30 described later, whereby the conductive particles 4 are converted into the terminal portions 17a, the electronic component 18, and the flexible substrate 21. By being crushed between each of the electrodes and being irradiated with ultraviolet rays by the ultraviolet irradiator 31, the conductive particles 4 are cured in a crushed state. Thereby, the anisotropic conductive film 1 electrically and mechanically connects the transparent substrate 12 to the electronic component 18 and the flexible substrate 21.

  In addition, an alignment film 24 subjected to a predetermined rubbing process is formed on both the transparent electrodes 16 and 17, and the initial alignment of liquid crystal molecules is regulated by the alignment film 24. In addition, a pair of polarizing plates 25 and 26 are disposed outside the transparent substrates 11 and 12, and these polarizing plates 25 and 26 allow transmitted light from a light source (not shown) such as a backlight to be transmitted. The vibration direction is regulated.

[Anisotropic conductive film]
As shown in FIG. 2, an anisotropic conductive film (ACF) 1 generally has a conductive particle-containing layer 3 formed on a release film 2 serving as a base material. As shown in FIG. 1, the anisotropic conductive film 1 has a conductive particle-containing layer 3 interposed between a transparent electrode 17 formed on a transparent substrate 12 of the liquid crystal display panel 10 and an electronic component 18 or a flexible substrate 21. By doing so, the liquid crystal display panel 10 and the electronic component 18 or the flexible substrate 21 are connected and used for electrical connection.

  As the release film 2, a base material such as a polyethylene terephthalate film generally used in anisotropic conductive films can be used.

  The conductive particle-containing layer 3 is formed by dispersing conductive particles 4 in a binder. The binder contains a film-forming resin, a curable resin, a curing agent, a silane coupling agent, and the like, and is the same as the binder used for a normal anisotropic conductive film.

  As the film-forming resin, a resin having an average molecular weight of about 10,000 to 80,000 is preferable. Examples of the film forming resin include various resins such as a phenoxy resin, an epoxy resin, a modified epoxy resin, and a urethane resin. Among these, phenoxy resin is particularly preferable from the viewpoint of film formation state, connection reliability, and the like.

  It does not specifically limit as curable resin, An epoxy resin, an acrylic resin, etc. are mentioned.

  There is no restriction | limiting in particular as an epoxy resin, According to the objective, it can select suitably. As specific examples, for example, naphthalene type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, triphenolmethane type epoxy resin, phenol aralkyl type epoxy resin, naphthol type epoxy resin, A dicyclopentadiene type epoxy resin, a triphenylmethane type epoxy resin, etc. are mentioned. These may be used alone or in combination of two or more.

  There is no restriction | limiting in particular as an acrylic resin, According to the objective, it can select suitably, For example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, for example , Trimethylolpropane triacrylate, dimethyloltricyclodecane diacrylate, tetramethylene glycol tetraacrylate, 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane 2,2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloxyethyl) ) Isocyanurate, urethane acrylate, epoxy acrylate. These may be used alone or in combination of two or more.

  The curing agent is not particularly limited as long as it is a photo-curing type, and can be appropriately selected according to the purpose. However, when the curable resin is an epoxy resin, a cationic curing agent is preferable, and the curable resin is an acrylic resin. In this case, a radical curing agent is preferable.

  There is no restriction | limiting in particular as a cationic hardening | curing agent, According to the objective, it can select suitably, For example, a sulfonium salt, onium salt, etc. can be mentioned, Among these, an aromatic sulfonium salt is preferable. There is no restriction | limiting in particular as a radical type hardening | curing agent, According to the objective, it can select suitably, For example, an organic peroxide can be mentioned.

  Examples of the silane coupling agent include epoxy-based, amino-based, mercapto-sulfide-based, and ureido-based agents. By adding the silane coupling agent, the adhesion at the interface between the organic material and the inorganic material is improved.

  As the electroconductive particle 4, any well-known electroconductive particle currently used in the anisotropic conductive film can be mentioned. Examples of the conductive particles 4 include particles of various metals and metal alloys such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, gold, metal oxide, carbon, graphite, glass, ceramic, Examples thereof include those in which the surface of particles such as plastic is coated with metal, or those in which the surface of these particles is further coated with an insulating thin film. In the case where the surface of the resin particle is coated with metal, examples of the resin particle include an epoxy resin, a phenol resin, an acrylic resin, an acrylonitrile / styrene (AS) resin, a benzoguanamine resin, a divinylbenzene resin, a styrene resin, and the like. Can be mentioned.

[Production method]
Next, a manufacturing process of a connection body in which the electronic component 18 and the flexible substrate 21 are connected to the transparent electrode 17 of the transparent substrate 12 through the anisotropic conductive film 1 will be described. First, the anisotropic conductive film 1 is temporarily pressure-bonded onto the transparent electrode 17. The method for temporarily press-bonding the anisotropic conductive film 1 is such that the conductive particle-containing layer 3 is on the transparent electrode 17 side on the transparent electrode 17 of the transparent substrate 12 of the liquid crystal display panel 10. Place.

  And after arrange | positioning the electroconductive particle content layer 3 on the transparent electrode 17, the electroconductive particle content layer 3 is heated and pressurized by the heating press head 30, for example from the peeling film 2 side, and the heating press head 30 is peeled from the peeling film 2. Release the release film 2 from the conductive particle-containing layer 3 on the transparent electrode 17, so that only the conductive particle-containing layer 3 is temporarily pressure-bonded onto the transparent electrode 17. Temporary pressure bonding by the heating and pressing head 30 heats the upper surface of the release film 2 while pressing it against the transparent electrode 17 side with a slight pressure (for example, about 0.1 MPa to 2 MPa). However, the heating temperature is set to such a temperature that the thermosetting resin such as epoxy resin or acrylic resin in the anisotropic conductive film 1 is not cured (for example, about 70 to 100 ° C.).

  Next, the electronic component 18 is disposed so that the transparent electrode 17 of the transparent substrate 12 and the electrode terminal of the electronic component 18 face each other with the conductive particle-containing layer 3 interposed therebetween.

  Next, ultraviolet rays are irradiated by the ultraviolet irradiator 31 disposed below the transparent substrate 12, the conductive particle-containing layer 3 is cured, and the electronic component 18 is connected to the transparent substrate 12. At this time, in this connection process, as shown in FIG. 3, the area | region where the terminal part 17a of the transparent electrode 17 and the electronic component 18 are connected is divided | segmented into a some connection area, and ultraviolet irradiation is carried out for every connection area | region. Stiffen the timing with different strengths.

  A region where the electrode terminal of the electronic component 18 and the terminal portion 17a of the transparent electrode 17 are connected is appropriately divided into a plurality of connection regions. For example, the electrode terminal of the electronic component 18 and the transparent electrode 17 are connected to each other. When forming a channel, it is divided for each channel. Or the area | region where the electrode terminal of the electronic component 18 and the terminal part 17a of the transparent electrode 17 are connected may divide | segment the whole area | region into a several area | region by an equal area. In FIG. 3, as an example, the electronic component 18 and the terminal portion 17a of the transparent electrode 17 are provided with five first to fifth connection regions CH1 to CH5 that are connected to form a channel. Show. 1st-5th connection area | region CH1-CH5 is substantially equal over the full width of the area | region where the terminal part of the electronic component 18 and the terminal part 17a of the transparent electrode 17 are connected via the anisotropic conductive film 1. FIG. Has been placed.

  The ultraviolet irradiator 31 is provided with first to fifth ultraviolet irradiators 31a to 31e corresponding to, for example, the first to fifth connection regions CH1 to CH5. The ultraviolet irradiator 31 can individually control the irradiation of the ultraviolet irradiators 31a to 31e, and in this connection step, it is possible to change the curing timing by changing the ultraviolet irradiation intensity for each connection region. . In addition, each ultraviolet irradiation part 31a-31e overlaps with an adjacent ultraviolet irradiation part, and an irradiation range overlaps, and it is made not to have the part which is not irradiated with an ultraviolet-ray.

  In this way, by changing the ultraviolet irradiation intensity and shifting the timing of curing, it is possible to sequentially connect the electronic component 18 and the transparent substrate 12 while absorbing distortion due to curing shrinkage in each connection region. This is because the binder begins to cure in the connection area irradiated with high-intensity ultraviolet rays, and when the binder shrinkage occurs, the adjacent connection area irradiated with lower-intensity ultraviolet rays still has high fluidity. This is because the strain due to curing shrinkage can be absorbed here.

  Specifically, in the first to fifth connection regions CH1 to CH5 shown in FIG. 3, as shown in FIG. 4, the third ultraviolet irradiation unit 31c increases the ultraviolet irradiation intensity, and the second and fourth ultraviolet rays. The ultraviolet irradiation intensity of the irradiation units 31b and 31d is next increased, and the ultraviolet irradiation intensity of the first and fifth ultraviolet irradiation units 31a and 31e is minimized. Accordingly, the conductive particle-containing layer 3 is cured in the order of the third connection region CH3 → the second and fourth connection regions CH2, CH4 → the first and fifth connection regions CH1, CH5. Thus, according to this connection process, the distortion at the time of hardening of 3rd connection area | region CH3 located in a center part by changing the intensity | strength of ultraviolet irradiation with respect to 1st-5th connection area | region CH1-CH5. The first and fifth connection regions CH1 adjacent to each other are absorbed by the uncured binder in the second and fourth connection regions CH2 and CH4 adjacent to each other, and distortion at the time of curing the second and fourth connection regions CH2 and CH4 is adjacent to each other. , Absorbed with an uncured binder of CH5.

  In contrast, when the first to fifth connection regions CH1 to CH5 are irradiated with ultraviolet rays at the same time, the connection regions CH1 to CH5 start to cure at the same time, so that the distortion of the adjacent connection regions can be absorbed. Can not. Therefore, according to this connection process, it is possible to suppress the distortion of the transparent substrate 12 and to prevent the connection failure of the electronic component 18.

  In this connection step, it is only necessary to shift the timing of curing by changing at least the intensity of ultraviolet irradiation. Furthermore, in order to finely adjust the timing of curing, the ultraviolet irradiation start of the first to fifth connection regions CH1 to CH5 is started. The timing may be shifted. Further, the end of the ultraviolet irradiation may be aligned or shifted.

  After the electronic component 18 is connected to the transparent electrode 17 of the transparent substrate 12, so-called FOG (film on glass) mounting is performed in which the flexible substrate 21 is mounted on the transparent electrode 17 of the transparent substrate 12 in the same manner. Thereby, the connection body by which the transparent substrate 12, the electronic component 18, and the flexible substrate 21 were connected via the anisotropic conductive film 1 can be manufactured. Note that these COG mounting and FOG mounting may be performed simultaneously.

  As described above, the COG mounting in which the liquid crystal driving IC is directly mounted on the glass substrate of the liquid crystal display panel and the FOG mounting in which the flexible substrate is directly mounted on the substrate of the liquid crystal display panel have been described as examples. It can be used for other various connections other than the FOG mounting.

  In the above example, an ultraviolet curable binder is used. However, the present invention may use light other than ultraviolet light as long as the binder can be cured by irradiation. Moreover, although the above example demonstrated the anisotropic conductive film 1 which has a film shape as a conductive adhesive, even if it is a paste form, there is no problem. In the present application, a film-like conductive adhesive film such as the anisotropic conductive film 1 containing the conductive particles 4 or a paste-like conductive adhesive paste is defined as an “adhesive”.

  Next, examples of the present invention will be described. In the present embodiment, a connection body provided with first to fifth connection regions CH1 to CH5 constituting five channels by connecting a transparent electrode provided on a glass substrate and an electrode terminal provided on an IC chip. By forming a sample (see FIG. 3), for each connected body sample, the connection state between the IC chip and the substrate is evaluated by the conduction resistance value (Ω), and the display unevenness is measured by the amount of warpage (μm) of the substrate. Substitute evaluation.

The ultraviolet-curing imparted anisotropic conductive film used for connection is composed of an adhesive layer composed of a conductive particle-containing layer (ACF layer) having a thickness of 18 μm. The ACF layer is
Phenoxy resin (YP-70: manufactured by Nippon Steel Chemical Co., Ltd.); 20 parts by mass liquid epoxy resin (EP-828: manufactured by Mitsubishi Chemical Corporation); 30 parts by mass solid epoxy resin (YD014 :) Nippon Steel Chemical Co., Ltd. 20 parts by mass of conductive particles; (AUL 704: manufactured by Sekisui Chemical Co., Ltd.); 30 parts by mass of cationic curing agent (LW-S1: manufactured by San Apro Co., Ltd.); The mixed solution was applied onto a PET film, dried in an oven, and formed into a film.

  This ACF was adjusted to have a thickness of 18 μm and laminated and laminated to obtain an anisotropic conductive film. The anisotropic conductive film used for an Example and a comparative example is width 4.0mm x length 40.0mm.

As an evaluation element,
External shape: 1.8mm x 34.0mm
Thickness: 0.5mm
Thus, an evaluation IC in which a continuity measurement wiring was formed was used.

  As an evaluation base material to which the evaluation IC is connected, a glass substrate having a glass thickness of 0.5 mm and having a continuity measurement wiring formed thereon was used.

  An evaluation IC was placed on the glass substrate through the anisotropic conductive film, and connected by thermal pressing with a heating press head and ultraviolet irradiation to form a connected body sample. The heat-pressing surface of the heating and pressing head is 10.0 mm × 40.0 mm, and the heat-pressing surface of the heating and pressing head is processed with a fluororesin having a thickness of 0.05 mm as a buffer material. The temperature conditions of the heating and pressing head are all 110 ° C., and the pressing conditions are 70 MPa and 5 seconds.

A UV irradiator (manufactured by OMRON) that irradiates ultraviolet rays was used having an intensity MAX (100%) → 500 mW / cm ² . The ultraviolet irradiation was performed for 5 seconds after applying pressure to the IC for evaluation with a heating and pressing head set at a predetermined temperature for 5 seconds. Table 1 shows the ultraviolet irradiation intensity in each of the connection regions CH1 to CH5 according to the example and the comparative example.

  In Example 1, the ultraviolet irradiation intensity of the third connection region CH3 was 90%, and the ultraviolet irradiation intensity of the first, second, fourth, and fifth connection regions CH1, CH2, CH4, and CH5 was 70%. . That is, in the first embodiment, among the first to fifth connection regions CH1 to CH5, the surrounding first, second, fourth, and fourth regions are stronger than the ultraviolet irradiation intensity irradiating the central third connection region CH3. This is an example in which the ultraviolet irradiation intensity of the fifth connection regions CH1, CH2, CH4, and CH5 is reduced and aligned. The ratio of irradiation intensity is 70/90 = 78%.

  In Example 2, the ultraviolet irradiation intensity of the third to fifth connection regions CH3 to CH5 is set to 70%, the ultraviolet irradiation intensity of the first connection region CH1 is set to 30%, and the ultraviolet irradiation intensity of the second connection region CH2 is set. Was 50%. That is, in Example 2, the ultraviolet irradiation intensity gradually increases from the first connection region CH1 serving as one end toward the other end, and the ultraviolet rays of the third to fifth connection regions CH3 to CH5 are increased. This is an example in which the irradiation intensity is aligned. The ratio of irradiation intensity is 30/70 = 43%.

  In the third embodiment, the ultraviolet irradiation intensity of the third connection region CH3 is 70%, the ultraviolet irradiation intensity of the second and fourth connection regions CH2 and CH4 is 50%, and the first and fifth connection regions CH1, The UV irradiation intensity of CH5 was 40%. That is, the third embodiment is an example in which the ultraviolet irradiation intensity is gradually reduced from the central third connection region CH3 toward the first and fifth connection regions CH1 and CH5 at both ends. The ratio of irradiation intensity is 40/70 = 57%.

  In the fourth embodiment, the ultraviolet irradiation intensity of the third connection region CH3 is 10%, the ultraviolet irradiation intensity of the second and fourth connection regions CH2 and CH4 is 30%, and the first and fifth connection regions CH1, The UV irradiation intensity of CH5 was set to 70%. In other words, the fourth embodiment is an example in which the ultraviolet irradiation intensity is gradually reduced from the first and fifth connection regions CH1 and CH5 at both ends toward the third connection region CH3 at the center. The ratio of irradiation intensity is 10/70 = 14%.

  In Comparative Example 1, the ultraviolet irradiation intensity of the first to fifth connection regions CH1 to CH5 was set to 100%, and they were uniform.

  In Comparative Example 2, the ultraviolet irradiation intensity of the first to fifth connection regions CH1 to CH5 was set to 10%, and they were uniform.

  In Comparative Example 3, the ultraviolet irradiation intensity of the first to fifth connection regions CH1 to CH5 was set to 50%, which was uniform.

  Under the above conditions, heat pressing and ultraviolet irradiation are performed to form a connected body sample in which the IC for evaluation is connected to the glass substrate. For each sample, the size of the warp (μm) and the conduction resistance value (Ω) are set. It was measured.

  As shown in FIG. 5, the warp measurement method is performed by scanning the stylus 41 from the lower surface of the glass substrate 40 of the joined body sample using a stylus type surface roughness meter (SE-3H: manufactured by Kosaka Laboratory Ltd.). Then, the warpage amount (μm) of the glass substrate surface after connection of the evaluation IC was measured.

  The conductive resistance value is measured by performing a high temperature and high humidity test in which the connected body sample is left in an environment of 85 ° C. and 85% RH for 500 hours, and then, as shown in FIG. An ammeter A and a voltmeter V were connected to the metal wiring 43 of the glass substrate 40 connected to 42, and a conduction resistance value was measured when a current of 1 mA was passed by a so-called four-terminal method using a digital multimeter. The results are shown in Table 2.

  First, the sample was irradiated with ultraviolet rays according to the ultraviolet irradiation intensity, and the reaction rate for each irradiation time was examined. The result is shown in FIG. From FIG. 7, it can be confirmed that there is a difference in curing time by changing the irradiation intensity and irradiating ultraviolet rays. Thereby, it turns out that a difference comes out in hardening timing by changing ultraviolet irradiation intensity. That is, the higher the ultraviolet irradiation intensity, the higher the reaction rate can be realized in a short time.

In addition, Table 2 shows the relationship between the ultraviolet irradiation intensity and the curing shrinkage rate of the anisotropic conductive films according to Examples and Comparative Examples. Curing shrinkage refers to the rate at which the anisotropic conductive film shrinks with ultraviolet curing,
Curing shrinkage = (ACF cured product specific gravity−ACF resin liquid specific gravity) / ACF cured product specific gravity × 100
Can be obtained.

  As shown in Table 2, in each example, the curing timing is shifted by shifting the ultraviolet irradiation intensity over the first to fifth connection regions CH1 to CH5, so that the connection region having a high ultraviolet irradiation intensity is cured. The strain is absorbed by the uncured binder in the adjacent connection area. Therefore, according to each embodiment, the amount of warping can be kept to 12.7 μm at the maximum, and the connection resistance can be kept to 11.6Ω at the maximum. Therefore, according to this connection process, it turns out that the distortion of a glass substrate can be suppressed and the connection failure of evaluation IC can be prevented.

  In each example, the third connection region CH3 in the center is irradiated with ultraviolet rays with the highest ultraviolet irradiation intensity, and the ultraviolet rays with the lower ultraviolet irradiation intensity are sequentially irradiated to the end portion in a stepwise manner. In addition, the amount of warpage and the connection in Example 4 in which the connection regions CH1 and CH5 at the end portions are irradiated with ultraviolet rays with the highest ultraviolet irradiation intensity, and the ultraviolet rays with the lower ultraviolet irradiation intensity are sequentially emitted toward the center portion. Resistance was relatively good. This is because a connection region that is not irradiated with ultraviolet rays is always provided in the connection region that is irradiated with ultraviolet rays, and in many connection regions, distortion during curing is absorbed by the uncured binder in the adjacent connection region. It is thought that it was possible to continue. In particular, since glass tends to be deformed outward from the central portion, the amount of warpage can be minimized in Example 4 in which ultraviolet rays are irradiated to the connection regions CH1 and CH5 at the end portions with the highest ultraviolet irradiation intensity. it can.

  Further, in each example, the warping amount tends to increase as the curing shrinkage rate increases, and as a result, display quality, display village, and the like are easily generated. For this reason, it turns out that it is more preferable to control a cure shrinkage rate small also in an Example.

  On the other hand, in the first comparative example in which the first to fifth connection regions CH1 to CH5 are irradiated with the same ultraviolet irradiation intensity of 100%, the connection regions CH1 to CH5 start to cure simultaneously, Further, since the cure shrinkage ratio was as large as 4.1%, it was not possible to absorb the distortion of the adjacent connection region, the largest amount of warpage was 18.1 μm, and the connection resistance was as large as 19.8Ω. Also in Comparative Example 3, the ultraviolet irradiation intensity is reduced to 50% and the ultraviolet irradiation intensity is reduced. However, since the connection regions CH1 to CH5 start to cure at the same time, the distortion of the adjacent connection regions is absorbed. The warpage amount was as large as 13.5 μm, and the connection resistance was as large as 13.3Ω.

  Further, in Comparative Example 2 in which the ultraviolet irradiation intensity was uniformed at 10% with respect to the first to fifth connection regions CH1 to CH5, the warpage was suppressed to 4.8 μm because the curing shrinkage rate was as small as 1.0%. However, the curing was insufficient and the connection resistance after the high-temperature and high-humidity test was as extremely high as 110.8Ω.

  Note that Example 3 and Comparative Example 3 are the same when viewing the integrated light quantity. However, the amount of warpage is smaller in Example 3 than in Comparative Example 3. This makes it possible to confirm that the amount of warpage is changed by varying the control of the irradiation intensity of the ultraviolet rays even when the amount of light received by the entire crimping part is the same, and further, the irradiation intensity of the ultraviolet rays is changed for each connection region. Thus, it can be confirmed that the curing timing can be shifted and the warpage can be reduced.

  Moreover, when the ratio of irradiation intensity | strength is seen, Examples 1-4 are 10 to 80% in general. On the other hand, the ratio of the irradiation intensity in Comparative Example 3 is 100%, and the amount of warpage is extremely large. In Comparative Example 2, all the irradiation intensity is 10%, resulting in poor connection. That is, in Examples 1 to 4, by setting the ratio of irradiation intensity to approximately 10% to 80%, it is possible to obtain a warp reduction effect due to a difference in curing speed while realizing a good electrical connection.

DESCRIPTION OF SYMBOLS 1 Anisotropic conductive film, 2 Release film, 3 Conductive particle content layer, 4 Conductive particle, 10 Liquid crystal display panel, 11 Transparent substrate, 12 Transparent substrate, 13 Seal, 14 Liquid crystal, 15 Panel display part, 16 Transparent electrode , 17 Transparent electrode, 17a terminal part, 18 electronic component, 20 COG mounting part, 21 flexible substrate, 22 FOG mounting part, 24 alignment film, 25 polarizing plate, 26 polarizing plate, 30 heating press head, 31 UV irradiator

Claims (7)

A step of placing electronic components on the substrate via a photo-curing adhesive;
Irradiating the adhesive with light and curing it,
A region where the substrate and the electronic component are connected is divided into a plurality of connection regions, and for each connection region, an irradiation unit that irradiates the light corresponding to the connection region is adjacent to the irradiation unit and partially irradiated The manufacturing method of the connection body with which the said electronic component was connected on the said board | substrate where the range overlaps and it changes and cures the said irradiation intensity of the light.   Irradiate the connection region other than the central connection region than the irradiation intensity of the light that irradiates the central connection region of the region where the substrate and the electronic component are connected among the connection regions divided into a plurality of regions. The method for manufacturing a connection body according to claim 1, wherein the light intensity is reduced and cured.   The manufacturing of a connection body according to claim 2, wherein the light intensity is gradually reduced and cured from the central connection region toward the connection region at an end of a region where the substrate and the electronic component are connected. Method.   Irradiate the connection region other than the connection region of the one or more end portions, rather than the irradiation intensity of the light that irradiates the connection region of the one or more end portions of the region where the substrate and the electronic component are connected. The method for manufacturing a connection body according to claim 1, wherein the light intensity is reduced and cured.   Step by step from the connection region at one end of the region where the substrate and the electronic component are connected toward the connection region at the other end of the region where the substrate and the electronic component are connected. The manufacturing method of the connection body of Claim 4 which hardens | cures by changing the irradiation intensity of the said light.   The light is stepwise from the connection region at a plurality of ends of the region where the substrate and the electronic component are connected toward the connection region at the center of the region where the substrate and the electronic component are connected. The manufacturing method of the connection body of Claim 2 made to harden by making irradiation intensity small. A step of placing electronic components on the substrate via a photo-curing adhesive;
Irradiating the adhesive with light and curing it,
A region where the substrate and the electronic component are connected is divided into a plurality of connection regions, and for each connection region, an irradiation unit that irradiates the light corresponding to the connection region is adjacent to the irradiation unit and partially irradiated An electronic component connecting method for connecting the electronic components on the substrate , wherein the ranges overlap and are cured by changing the irradiation intensity of the light.